good news on american census data

Last week, President Obama signed the 2010 Consolidated Appropriations
Act, an amalgam of six separate appropriations bills providing $447
billion to an array of federal departments. A small fraction of this
funding is devoted to supporting federal statistical agencies that
generate the demographic, economic, and social data that will help
metros better understand themselves. ...

The bill also funds the Census Bureau to develop, for the first time, detailed American Community Survey
data at the neighborhood level. These data, on such varied topics as
income, housing costs, and journey to work, mirror those once collected
by the traditional decennial “long form.” Except now communities will
get an update every year from 2010 forward. The tradeoff—the data come
in five-year averages, for 2005-2009 the first time out.

The question about the number of vehicles in the household, when combined with questions about location and income, can help us tell stories about the effects of walkable, transit-intensive communities on car ownership. This, in turn, can be directly relevant to parking policy, which has huge impacts on transit patronage and other urbanist outcomes.

Even in enlightened Vancouver, for example, newly built residential towers generally have huge multi-level basements full of parking. I lived in one of them (1295 Richards) in 2006, and was struck by how many spaces were vacant even overnight. Many residents, including myself, were forced to pay for parking that they almost never used -- an obvious example of shifting the costs of motoring onto non-motorists. Only by tracking the decline of car ownership (by small zone as the ACS does) can we make the case for lower parking requirements in transit-intensive places.

Such an analysis would of course have to track not just zero-car households but also households where there are fewer cars than adults. Couples, for example, need two cars to live in sprawl, but can often share one if they have good transit, bike, and walking options. Because political battles about parking are always very local, we need this data for the smallest possible zones, and this looks like a step in that direction.

Journey to Work

The "journey to work" questions ask about exactly where people commute to, how long it takes, and the mode they use for that purpose. This data is very important for assessing how mode choice decisions are changing in response to various local circumstances, including the availability of the various options. It is not clear whether they will have a large enough sample to be significant as a count of how many people commute between any pair of neighborhoods, but at least we will be able to talk more precisely about the commute behaviors from each neighborhood, and to each employment area.

Unfortunately, the mode question doesn't allow people to describe trips involving combinations of modes, such as Park-and-Ride.

Overall, the neighborhood-level American Community Survey is going to be a great thing. It will present in rolling averages of the last five years, so it will show a bit if a lag, but it's an important step. You can't fix what you can't quantify.